The present invention generally relates to an improved machine for use in connection with the fabrication of jewelry, specifically rope chains and more particularly relates to an automatic soldering machine for automatically applying solder paste to rope chains and automatically heating the solder paste.
A rope chain is a chain in the form of a rope constituted by a helical series of open rings that are interlinked with one another to define a configuration similar to a continuous double-stranded rope.
Prior machines of the general character indicated are exemplified by Tega et al., U.S. Pat. No. 4,127,987,; Tega, U.S. Pat. No. 4,311,9001, and Allazzetta et al., U.S. Pat. No. 4,503,664. Allazzetta et al. is specifically directed to a machine by which the fabrication of rope chains is automated. The subject patent notes that linking the open rings found in a rope chain requires great dexterity, manual agility and uninterrupted concentration on the part of the workmen. It further notes that the production of these chains by hand involves long periods of time and consequently is very labor-intensive and leads to a high selling price.
The Allazzetta rope chain fabricating machine and, indeed, several earlier machines have concentrated on automating the process of assembling and interlinking the open rings of a rope chain, in a manner which imparts to the rope chain its characteristic look. The shape of the rope chain is maintained in these machines by reinforcing wires which are threaded through the chain.
In the known production process, subsequent to the automatic assembling of the chain, solder paste is manually or automatically applied between pairs of adjacent rings of the rope chain, the chain is manually heated and the solder sets. Thereafter, the reinforcing wires are removed.
Weinberg et al., U.S. Pat. No. 5,115,959, to which the improvement of the present invention is directed and which is incorporated herein by reference is specifically directed to a machine by which the soldering operation is automated.
Specifically, Weinberg et al. is directed to a mechanism for feeding and soldering a rope chain 10 (FIG. 1) in the form of a rope constituted by a helical series of open rings 13 (FIGS. 2(a) and 2(b)), in which adjacent rings 13 are interlinked to define a configuration similar to a continuous double-stranded rope. More specifically, it is comprised of a first, continuous strand of links 21 intertwisted with a second continuous strand 23. The rope chain 10 is preassembled, either manually or automatically, by forming, feeding and interlinking the rings 13 and the shape thereof is temporarily maintained by reinforcing wires 11 which are threaded through it. Thereafter, the open rings 13 are soldered to one another and the reinforcing wires 11 are removed, enabling the chain 10 to maintain its characteristic rope chain shape.
Thus, in the soldering machine described by Weinberg et al., a preassembled, unsoldered rope chain 10 (FIG. 2(a) and 2(b)) is fed as shown in FIG. 1 to emerge above a platform 12 which supports a rope chain feeding mechanism 9 for feeding the rope chain 10. After each stepped advancement of the rope chain 10, a first and second solder-applying hollow needle 38 and 40 is moved laterally to apply a controlled, measured amount of solder paste to the rope chain 10, on diametrically opposed sides thereof and precisely at the link junction 31, 33, etc. that are at that instant positioned at the soldering position 20 adjacent the hollow needles 38 and 40.
For ease of presentation, the needles 38 and 40 have been drawn in FIG. 1 at an exaggerated distance away from the gears 14 and 16, whereby their respective needle tips 39 and 41 are able to contact the rope chain at a solder position 20 which is located at or very near the point where the chain is engaged by the gears 14 and 16.
With the needles 38 and 40, a first dab of solder is applied at a link junction 31 on the first strand 21 and a second dab of solder is applied to the link junction 31 on the second strand 23.
In a known soldering machine similar to the soldering machine disclosed in Weinberg et al., the rope chain 10 is advanced (and soldered) until a portion of the rope chain 10 which contains unheated solder reaches a predetermined height, at which point, the advancing and soldering operations are halted. When the soldering machine has stopped advancing the rope chain 10, an operator of the soldering machine heats (or "burns") that portion of the rope chain which contains unheated solder with a blow torch until the solder flows and sets, securing the rings to one another. The manual operation of heating the rope chain 10 takes approximately three to five minutes and upon completion of manual heating, the operator pushes a button on a control panel (not shown), causing the soldering machine to repeat the above described operation of advancing and soldering the rope chain.
A rope chain pulling system 24 for the above-described soldering machine comprises pulleys 25, a support 27, a weight 29, and a coupling 35. The lower portion 43 of the coupling 35 is rotatable relative to its upper portion enabling the system 24 to pull the rope chain and maintain it taut while it is being slowly rotated by the feeding mechanism 9.
In the above described soldering machine, a soldering station 7 (FIG. 1) has a pair of L-shaped brackets 60 which are secured at one end thereof to the platform 12. The solder-applying needles 38 and 40 are coupled to solder paste reservoirs 62 that are secured to reciprocally movable blocks 64, which slide on the short arms 66 of the brackets 60 in the directions indicated by the arrows 68.
FIGS. 3, 4(a) and 4(b) illustrate the soldering mechanism 7 which includes a shell 70 pivotally supported by laterally extending hinge pins 72 in a stand 74. As seen in Fig. 4(a), the shell 70 has an axially extending bore 76 and a threaded opening 78 in which a solder container 80 is threadably secured. An orifice 82 leads from the opening 78 into the bore 76.
The solder-applying needle 38 extends from a rod 84 that is reciprocally movable within the axial bore 76 and which has defined in it an axially extending solder duct 86 which is in communication with the hollow needle 38. A radially extending orifice 88 of the solder duct 86 communicates with the orifice 82 of the shell 70 when aligned as shown in FIG. 4(b), enabling solder paste to flow from the container 80 into the solder duct 86.
At its other end 90 (FIG. 3), the rod 84 is pivotally connected to a pulley 92, at a position on the pulley 92 eccentric to a pin 94 about which the pulley 92 is rotatably supported on the support 96. As the pulley 92 rotates in the direction of the arrow 98, through a motive power provided either from the gear box 28 via a coupling or belt 32 (FIG. 1), or through its own source of motive power, the rod 84 reciprocates in a manner whereby the needle tip 39 traverses the elliptical path 100 going through points A, B, C, D corresponding to the positions A, B, C, D of the pulley 92. The previously mentioned soldering position 20 corresponds to needle position D. Preferably, the coupling 32 and gear box 28 are configured to synchronize the motions of the gears 14 and 16 and the needles 38 and 40, in a manner whereby the needles 38 and 40 reach the soldering position 20 immediately after the arrival thereat of a next link junction 31, 33, etc.
Each of the gears 14 and 16 is rotated by respective one of the gear boxes 26 and 28 (FIG. 1) which are in turn driven by a motor 34 under the control of a motor controller 36. The motor controller 36 energizes the motor 34 in discrete sequential steps. This sequentially rotates the gears 14 and 16 and serves to rotate and advance the rope chain 10 by the equivalent of one rope chain link, corresponding to the advancement of the gear teeth 18 by one gear tooth.
In operation, at the position A, the needle tip 39 is moving away from the soldering position 20 (FIG. 3). At position B, the orifices 82 and 88 become aligned (FIG. 4(b)), enabling solder paste held under pressure in the hanging solder 102 at the tip 39 of the needle 38. Thereafter, as the pulley 92 traverses through the positions C and D, the needle tip 39 traverses a path that enables it to wipe the solder dab 102 against the link junction 31, 33, etc., then located at the soldering position 20. This completes a single solder-applying cycle.
The soldering mechanism of FIGS. 3, 4(a) and 4(b) is repeated for the needle 40, so that two dabs of solder are simultaneously applied on opposed diametrical sides of the rope chain 10. The amount of solder that is applied is controlled by controlling the pressure of the solder in the container 80 as well as by controlling the dwell time of the pulley 92 at the position B and by careful selection of the cross-sectional sizes of the solder passageways in the rod 84, the needle 38, and orifices 82 and 88.
Another solder-applying mechanism 7 is disclosed in Weinberg et al. and illustrated in FIG. 5(a) to 5(d), and depicts a modified shell or block 110 which is horizontally disposed and reciprocally movable in an opening 112 provided in a fixed base 114. The block 110 has a rear flange 116 and a compressed spring 118 on its outer circumferential surface which is biased to urge the flange 116 rearwardly, against a stop 120. A solder chamber 122 in the forward portion of the block 110 communicates with the threaded opening 124 for the solder container 80 (FIG. 3). The front end of the solder chamber 122 is bounded by a plug 126 (FIG. 5(b)) which supports the hollow needle 38.
At the rear, the block 110 defines a rear chamber 128 in which a solid ram rod 130 having a solid needle 132 with a sharp tip 134 is reciprocally arranged. The solid needle 132 slides within a connecting passageway 136 that connects the rear and the front chambers 122 and 128 of the block 110.
In operation, initially, as shown in FIG. 5(a), the rod 130 begins to move to the right in the direction of the arrow 140 while the block 110 remains stationary. This causes the tip 134 of the solid needle 132 to retreat from the entrance point 142 into the hollow needle 38, allowing solder paste to flow from the container (not shown) via the solder chamber 122 into the needle 38.
In the next step (FIG. 5(c)), the ram rod 130 reverses direction as shown, the entrance of the solid needle 132 into the chamber 122 causing some of the solder paste to issue from the hollow needle 38, creating a solder dab 102 the size of which is determined by the mass size of the solid needle 132 and the degree of penetration of the tip 134 into the hollow needle 38.
In the final step (FIG. 5(d)), continued forward movement of the rod 130 serves to push the entire block 110 forward by a distance "d" in a manner which enables the tip of the needle 38 to reach the soldering position 20 and apply the solder dab 102 to the rope chain 10.
One difficulty encountered with the above-described soldering machine is the general inability to operate the soldering-machine unattended for an extended period of time. Because of the necessity to manually heat a portion of the rope chain 10 at relatively short intervals of time, an operator must check the soldering machine at regular intervals to determine if the rope chain 10 is ready to be heated, and if it is ready to be heated, spend three to five minutes of time to heat that portion of the rope chain which contains unheated solder. In addition, since the heating process is performed manually, there is the risk that such heating may be performed improperly, thus resulting in a rope chain whose links are not properly joined or a rope chain that is weak or deformed because of overheating.
Weinberg et al. discloses a heater system which allegedly overcomes the above-described difficulties. As shown in FIG. 1, a heater 48 is coupled to a heater controller 50 which provides electrical power to the heater 48 and may be linked to the motor controller 36 by an electrical line 52 by which it may be possible to disable the heater/controller 50 when the motor 34 has ceased running, thus preventing overheating of the rope chain 10. In addition, an input from the heater controller 50 to the motor controller 36 may be used to disable the motor 34 until such time as the heater 48 has reached a predetermined temperature.
One difficulty encountered with the above-described heating system is the general inability in maintaining an induction heater 48 which is capable of properly heating the rope chain such that the solder will flow and properly set, joining the links, without overheating that portion of the rope chain 10 which passes through the induction heater 48. As it is known, the type of solder used with gold rope chain, for example, contains a large percentage of gold whereby even slight overheating by induction heater 48 will damage the rope chain. In addition, should the induction heater 48 fail and therefore not properly heat the rope chain 10, the solder applied to the rope chain 10 will not flow, thereby providing a rope chain that requires manual heating as described above. Further, should motor 34 fail, thus resulting in the rope chain not advancing, heater 48 is dependent upon heater controller 50 and motor controller 36 to prevent overheating of the rope chain 10, whereby this circuitry is complex and may easily fail. Still further, heater 50 requires a period of time to heat-up in order to reach a predetermined temperature thus resulting in a wait period before the soldering machine is functional each time the soldering/heating operation is halted.